Deciphering the roles of RIFIN and STEVOR parasite antigens in severe malaria pathogenesis via transcriptomics and immune profiling

通过转录组学和免疫分析破译 RIFIN 和 STEVOR 寄生虫抗原在严重疟疾发病机制中的作用

• 批准号: 10748822
• 负责人: Jonathan Lawton
• 金额: $ 3.42万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10748822
• 关键词: Acute; Adherence; Africa South of the Sahara; African; Age; Amino Acid Sequence; Antibodies; Antibody Response; Antigens; Binding; Blood; Blood specimen; Blood typing procedure; Cell Surface Proteins; Cells; Cerebral Malaria; Child; Clinical; Clinical Research; Complex; Convalescence; Custom; Development; Disease; Epidemiologist; Erythrocyte Membrane; Erythrocytes; Falciparum Malaria; Family; Gene Expression; Generations; Genetic Polymorphism; Genome; Geographic Locations; Glycophorin C; Goals; Human; Immune; Immunity; Immunologic Epidemiology; In Vitro; Individual; Infection; International; Invaded; Investigation; Laboratory Study; Length; Link; Malaria; Malawi; Mali; Measures; Mediating; Mediator; Membrane Proteins; Messenger RNA; Molecular; Morbidity - disease rate; Open Reading Frames; Parasites; Pathogenesis; Pattern; Plasmodium falciparum; Predisposition; Preparation; Protein Family; Protein Microchips; Proteins; RNA; Research; Research Design; Risk; Risk Factors; Role; Sampling; Serology; Serum; Severities; Site; Subgroup; Surface; Surface Antigens; Symptoms; Syndrome; Therapeutic; Time; Training; Transcript; Uganda; Vaccines; Variant; Virulence; Vulnerable Populations; blood group; career; design; disease phenotype; immune clearance; malaria infection; malaria transmission; malarial anemia; mortality; next generation; novel strategies; preference; reference genome; response; skills; transcriptome sequencing; transcriptomics; vaccine development

PROJECT SUMMARY Despite decades of research, Plasmodium falciparum malaria continues to kill hundreds of thousands of children in sub-Saharan Africa each year. Vulnerability to severe malaria is complex, involving both host and parasite factors. Blood type A is an established risk factor for severe malaria, whereas blood type O is associated with protection from complicated symptoms. The exact mechanism of this phenomenon is incompletely understood but may involve interactions mediated by particular parasite antigens. RIFINs and STEVORs are highly diverse parasite protein families that are displayed on the surface of infected red blood cells. Recent laboratory studies suggest that these antigens may exacerbate malaria severity through multiple mechanisms, including adherence to nearby red blood cells to form “rosettes” that envelop the parasite and protect it from immune clearance. Certain RIFINs bind preferentially to type A red blood cells. STEVORs have a similar binding preference for glycophorin C, another red blood cell surface protein. These intriguing findings suggest that RIFINs and STEVORs may be central to P. falciparum virulence and drive differences in susceptibility to severe disease between blood types. Despite promising in vitro links to severe malaria vulnerability, the immense diversity of the RIFIN and STEVOR families has so far precluded the comprehensive study of these antigens in clinical infections. The goal of this proposal is to identify RIFIN and STEVOR subtypes that are associated with severe malaria in African children. We will obtain blood and serum samples from children with severe or non-severe malaria in Mali, Malawi, and Uganda, representing three regions of sub-Saharan Africa with distinct malaria transmission patterns. In Aim 1, we will identify the expressed rif and stevor transcripts in individual blood samples using reference-free RNA-Seq, then compare the abundance of transcript subgroups between severe and non-severe malaria. In Aim 2, we will profile antibody responses against a comprehensive microarray of RIFIN and STEVOR variants to identify immune “gaps” in children with severe malaria compared to non-severe malaria. RIFIN and STEVOR antigen subtypes that were preferentially expressed and/or not serorecognized in severe malaria infections may be important mediators of pathogenesis. RIFINs that predominate in severe cases with blood type A may be critical aspects of this group’s vulnerability. The proposed aims will help clarify the role of RIFINs and STEVORs in severe malaria pathogenesis and inform the development of tailored vaccines and therapeutics to protect the most at-risk children in sub-Saharan Africa. The applicant will develop and apply hands-on skills in transcriptomics, immunoepidemiology, and international clinical research design and management, critical to his intended career as a 21st century molecular epidemiologist.

项目概要 尽管经过数十年的研究，恶性疟原虫疟疾仍然导致数十万儿童死亡 每年在撒哈拉以南非洲地区。严重疟疾的脆弱性很复杂，涉及宿主和寄生虫 因素。 A 型血是严重疟疾的既定危险因素，而 O 型血则与 预防复杂症状。这种现象的确切机制尚不完全清楚 但可能涉及由特定寄生虫抗原介导的相互作用。 RIFIN 和 STEVOR 高度多样化 显示在受感染红细胞表面的寄生虫蛋白家族。最近的实验室研究 表明这些抗原可能通过多种机制加剧疟疾的严重程度，包括依从性 附近的红细胞形成“玫瑰花结”，包裹住寄生虫并保护其免受免疫清除。 某些 RIFIN 优先与 A 型红细胞结合。 STEVOR 有类似的绑定偏好 血型糖蛋白C，另一种红细胞表面蛋白。这些有趣的发现表明 RIFIN 和 STEVOR 可能是恶性疟原虫毒力的核心，并导致严重疾病易感性的差异 血型之间。尽管在体外与严重疟疾脆弱性之间存在着有希望的联系，但巨大的 RIFIN 和 STEVOR 家族的多样性迄今为止阻碍了对这些家族的全面研究 临床感染中的抗原。该提案的目标是确定 RIFIN 和 STEVOR 亚型 与非洲儿童的严重疟疾有关。我们将从患有以下疾病的儿童身上获取血液和血清样本 马里、马拉维和乌干达代表撒哈拉以南非洲三个地区的严重或非严重疟疾 具有独特的疟疾传播模式。在目标 1 中，我们将鉴定表达的 rif 和 stevor 转录本 使用无参考 RNA-Seq 分析单个血液样本，然后比较转录子亚组的丰度 严重疟疾和非严重疟疾之间。在目标 2 中，我们将针对全面的抗体反应进行分析 RIFIN 和 STEVOR 变体微阵列可识别严重疟疾儿童的免疫“缺口” 至非严重疟疾。优先表达和/或不表达的 RIFIN 和 STEVOR 抗原亚型 在严重疟疾感染中识别的血清可能是发病机制的重要介质。 RIFIN 认为 A型血在严重病例中占主导地位可能是该群体脆弱性的关键方面。拟议的 目标将有助于阐明 RIFIN 和 STEVOR 在严重疟疾发病机制中的作用，并告知 开发定制疫苗和治疗方法，以保护撒哈拉以南非洲地区高危儿童。这 申请人将发展并应用转录组学、免疫流行病学和国际化方面的实践技能 临床研究设计和管理，对于他作为 21 世纪分子生物学家的职业生涯至关重要 流行病学家。